Hello.
I designed our product by applying AD5111 (10K, Up/Down).
It worked normally once or twice, but it is currently fixed at A-W 45 ohm and W-B 9.8K ohm, and does not respond to any commands.
Sometimes when power is applied again, it becomes A-W 9.8K ohm, W-B 39 ohm.
The strange thing is that the resistance of A-B is measured around 9.8K.
Judging by the resistance value, it doesn't seem like a malfunction. What's the problem?
PS - Of course, other AD5111s are operating normally when tested by connecting them to the same signal port.
Thanks in advance for your kind reply.
Please share the circuit diagram and the power supply sequencing details.
Does the part respond to U/D state?
Hi, vsethia.
Thank you for your kindness.
I answer your question as follows.
1. Please share the circuit diagram and the power supply sequencing details.
-> Power is supplied directly from AD/DC 5V power.
The sensor signal(A/sens_2, W/sens_1, B/sens_3) connection is controlled using the photo relay (control line SW_COMP_VDIV-FCC).
(Of course, SW_COMP_VDIV-FCC is maintained High level at initial and normal.)
Can the power supply sequencing have a critical effect on the behavior of a part?
2. Does the part respond to U/D state?
-> In U/D state, parts do not respond.
Until the AD5111 is powered up, the relay control SW_COMP_VDIV_FCC is set to high (5V) and no signals are applied on A, W, B terminals. Is that correct?
What are the voltages on the sens_1, sens_2 and sens_3 signals?
What is the SW_COMP_VDIV_FCC when you try to turn on the relays.?
What is the state of /CS and SCLK when you try to update the wiper position?
Until the AD5111 is powered up, the relay control SW_COMP_VDIV_FCC is set to high (5V) and no signals are applied on A, W, B terminals. Is that correct?
-> Yes.
What are the voltages on the sens_1, sens_2 and sens_3 signals?
-> sens_2 = 0.2V, sens_3 = 0V (GND), sens_1 = 0.193V ~ 0.027V
What is the SW_COMP_VDIV_FCC when you try to turn on the relays.?
-> If it means the control signal voltage level of SW_COMP_VDIV_FCC at relay turn on, it is changed to High(5V) -> Low(0V).
On the other hand, it is changed to Low(0V) -> High(5V) at relay turn off.
What is the state of /CS and SCLK when you try to update the wiper position?
-> /CS is Low and /CLK is High -> Low
I have a question.
If a signal is connected to another port before power is applied to VDD/GND, can AD5111 be broken?
On your last query, please elaborate with a circuit diagram.